We’ve known for decades that chimpanzees and their smaller cousins the bonobos have the ability to learn some human sign language. They also use their own signs and gestures in the wild, but until recently most research had focused on teaching them to communicate on our terms.

However, in two new studies published earlier this month, researchers were able to decode some of the apes’ own gestures.

The first study looked at a group of chimpanzees in the wild. Over a period of 18 months, primatologists carefully noted every gesture the chimpanzees seemed to be using for communication, as well as how each gesture was responded to by other chimps. Then, the researchers used computer analysis to break down the data and find out which gestures seemed to have consistent meanings. They were able to uncover 36 commonly used and understood gestures, with 15 different meanings.

Study co-author Richard Byrne, a primatologist at the University of St. Andrews, told Wired,

“What we’ve shown is a very rich system of many different meanings. We have the closest thing to human language that you can see in nature.”

The other study, from the University of Neuchâtel in Switzerland, decoded a complex hand sign used by bonobos. Bonobos are the free-love hippies of the primate world; they are known for having sex and lots of it. So, it’s only appropriate that researchers translated the gesture to mean something like “Hey baby, let’s you and me go someplace where we can be alone together.”

Dr. Catherine Hobaiter, the other co-author of the chimpanzee study told the BBC that the way the chimps used gestures indicated that they are closer to us linguistically than we might like to believe:

“The big message [from this study] is that there is another species out there that is meaningful in its communication, so that’s not unique to humans. I don’t think we’re quite as set apart as we would perhaps like to think we are.”

However, not everyone agrees. Evolutionary biologist Dr. Susanne Shultz, of the University of Manchester, told the BBC that the study’s results were “a little disappointing”. She went on to say,

“The vagueness of the gesture meanings suggest either that the chimps have little to communicate, or we are still missing a lot of the information contained in their gestures and actions.”

It’s quite possibly the latter. Dr. Hobaiter told Wired that she believed their ability to analyze and understand chimpanzee gestures was limited at best:

“I have the impression that there were some meanings we couldn’t capture,” Hobaiter said. Sometimes, she recalled, a chimpanzee would gesture to another, then appear satisfied, though nothing else seemed to happen. Said Hobaiter, “I’d love to know what was going on!”